Process of manufacturing protocatechuic aldehyde.



UNITED STATES "PATENT OFFICE.

GERHARD STALMANN, OF LEIPZIG-GOHLIS, GERMANY, ASSIGNOR TO THE FIRM OF SCHIMMEL U. (30., OF MILTITZ-LEIPZIG, GERMANY.

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Specification 0! Letters Patent.

Patented April 28, 1908.

Application filed October 6, 1905. Serial No. 281,525.

To all whom it may concern:

Be it known that I, GEBHARD STALMANN,

doctorof philosophy, chemist, a subject of the King of Prussia, German Emperor, residing at 20 Bismarckstrasse, Lei zig-Gohlis, Kingdom of Saxony, German mpire, have invented new and useful Im rovements in Processes of Manufacturing rotocatechuic Aldehyde, of which the following is a specification.

The present process is based upon the fur halogenized is that mainly dichloro iperonal is obtained, whereas with phosp orus entachlorid firstly piperonal chlor1d and ater on dichloropi eronal chlorid are formed. The reaction may e expressed by the following equation:

Upon boiling with water the produced .chlorinized methylene ether, the dichloropiperonal is decom osed into *protocatechuic al ehyde, hydroc oric acid, and carbonic acid: 1

decomposed as above by bo' ing with water.-

Or bromin may be allowed to drop into a mixture of piperonal and sulfur heated to about 130, Gent. or bromin vapor may be introduced into the mixture, decomposition being then effected by boiling with water.

Inplaceof thehalogen com ounds ofsulfur, sulfuryl chlorid may also e used. This compound also likewise does not chlorinize the aldehyde group, but only the methylene group the sense of the following equation:

With the same success as piperonal, chlorid of piperonal may also be converted into dichloro- .i eronal chloridbymyprocess, andthis may e roken down in the known manner into protocatechuic aidehyde, hydrochloric acid, and carbonic acid. v

In order to describe my process more fully, I give the following examples as illustrations for carrying "out my process:

I. 15.4 k1lograms.of piperonal are heated with 26.8 kilograms of protochlorid of sulfur to about, 130 Cent. As soon as the initially somewhat vigorous generation of hydro chlo'ric acid is ended, the' mixture is submitted to a boiling with water for about 8' hours, a uniform stream of carbonic acid escaping during this time. After the evolution of carbonic acid is finished, it is filtered from the sulfur separated and theprotocatechuic aldehyde is extracted from the aqueous solution with ether.

II. 15.4 kilograms of piperonal are heated with. 26.8 kilo afns of sulfuryl chlorid. to about 80. Af t er the reaction (which takes place somewhat impe'tuously) is finished, the product is boiled wlth water and after coolm the protocatechuic aldehyde is extracte with ether. 1 v 4 III. 22.2 kilograms of piperonal chlorid are treated with 20.4 kilograms of dichlorid of sulfur asin Exam l e I, but with the addition of 8 kilograms of toluene. After the reactionproduct has been decom osed by treating with water; the toluene is lown off with steam and the protocatechuic aldehyde is isolated as above.

IV. Into a mixture of 15.4 kilograms of piperonal and about 5 kilograms of sulfur,

eated to say 1309 Cent, 14 kilograms of chlorin are gradually introduced. There upon the mixture'is heated until the genera-' tion of hydrochloric acid is finished, when.

the reaction product is treated' as in the above examples. v

What I claim as my invention and desire to secure by. Letters-Patent is z 1. The process for manufacturmg prot'o catechuic aldeh de which consists in heating piperonal with alogen-compound's of sulfur and boiling the product formed with water;- process for manufacturing prot0- with water.

3. The process for manufacturing protocatechuic aldehyde which consists in heating pipero'nal with sulfur and introducing a Haloe'n into the mixture and boiling the product ormed with water.

4; The process for manufacturing-prom catechuic aldehyde which'consists in heating piperonal with sulfur and solvents and introducing a halogen into the mixture and boil'-.

in the produ'ctformed with water.

n testimony whereof I have signed my name to this specification in the presence of two subscribin witnesses.

. EBHARD STALMANN. Witnesses:

ERNST Fmrzsonn, RUDOLPH FRI KE. 

